A Phytopathogenic Cysteine Peptidase from Latex of Wild Rubber Vine Cryptostegia grandiflora

作者：Ramos M V^*; Souza D P; Gomes M T R; Freitas C D T; Carvalho C P S; Junior P A V R; Salas C E

来源：Protein Journal, 2014, 33(2): 199-209.

DOI：10.1007/s10930-014-9551-4

• Apocynaceae
• Enzyme
• EC 3.4.22.16
• Laticifer
• Plant defense
• Propidium iodide

A 24,118 Da (MALDI-TOF) cysteine peptidase (EC 3.4.22.16) was purified from the latex extract of Cryptostegia grandiflora by two chromatographic steps involving ion exchange and Reverse-phase HPLC. The purified protein (Cg24-I) exhibits a single band profile following reduced SDS-PAGE and a unique amino terminal sequence, (1)VPASIDWREKGTVL(14), that is similar to other plant cysteine peptidases. Cg24-I displayed optimal proteolytic activity at pH 8.0 with 25 mM phosphate buffer. The proteolytic activity was inhibited with 0.2 mM E-64 and 1 mM iodoacetamide and was stimulated with 1 mM DTT. Cg24-I fully inhibited spore germination of phytopathogenic fungi Fusarium solani at a dose of 28.1 mu g/mL. Its toxicity involves the membrane permeabilization of spores as probed by propidium iodide uptake. These results show that latex peptidases are part of the plant%26apos;s defensive strategy against phytopathogens and that they most likely act synergistically with other recognized defensive proteins.

• 出版日期2014-4